Rebecca Katz (right) is a chef who helps cancer patients learn how to eat and even enjoy food during chemo.

Courtesy of Rebecca Katz

Cancer patients often lose their appetite because chemotherapy can cause nausea. But it does something else to make food unappetizing – it changes the way things taste.

Hollye Jacobs was diagnosed with breast cancer in 2010, at the age of 39. As a nurse she expected the extreme nausea that often accompanies powerful chemo therapy drugs. But as a patient, she wasn't expecting the taste changes.

"Nothing tasted good, nothing was appealing, I didn't have any desire whatsoever to eat," Jacobs, of Santa Barbara, Calif., says. Food tasted like cardboard, textures were mealy and there was a near chronic taste of metal. "The metal mouth was horrible, even just saying it again, I can taste it," she says.

This "metal mouth" is caused by the chemo. When medications are injected into the bloodstream, they also get into the saliva, and most medications have a very bitter taste, according to researcher Beverly Cowart, who studies taste and smellat the Monell Chemical Senses Center in Philadelphia.

Then there's another unpleasant side effect of chemo drugs. Foods just don't taste the same. They're often too sweet, too salty, too bitter or without taste at all.

Jacobs says she used to love pasta with marinara sauce, but during treatment, "one day I ate it, it literally was absolutely repulsive," she says. "It tasted like cardboard and the tomato sauce almost had a stinging sensation in my mouth."

One reason the taste of food changes has to do with the nature of chemo therapy itself, Cowart says. The purpose is to attack cancer cells which grow rapidly. "Unfortunately, taste cells are the same, " says Cowart. "They turn over very fast." This means the chemo drugs end up targeting the taste cells along with the cancer cells.

There are some things patients can do to retain their interest in food, according to Rebecca Katz. She is a chef who works with cancer patients, helping them learn how to eat and even enjoy food during treatment. Her books, The Cancer-Fighting Kitchen, and One Bite At A Time, offer lots of suggestions.

First off, try tricking your taste buds, Katz says. Use new flavors and spices, so there's no expectation of how foods should taste. "Give your taste buds a passport for worldwide travel," to countries like Thailand, Latin America, Spain and Morocco. Introduce new spices like cumin, cinnamon, coriander, and "all of a sudden your taste buds are tickled instead of drab," she says.

Then there are some very practical changes patients can make. If water or food tastes like metal add a little acid, says Katz, the type found in lemons, limes and oranges. If you feel like you are eating cardboard, add salt. Sea salt is best because it's not processed like typical table salt. If foods taste bitter or harsh, she says, a teeny drop of Grade B organic maple syrup will make it taste better.

As for fats, Katz says, "eat them!" She suggests the healthiest ones, like olive oil, coconut oil, nuts and seeds. Fat is a natural flavor carrier. "Fat is like a magic carpet traversing back and forth across your palate, delivering tastes," she says, "so all of a sudden you have that involuntary spasm of vocal delight, turning yuck into yum."

Katz calls this her "culinary pharmacy," with the acronym FASS standing for fat, acid, salt and sweet. And for cancer patients FASS can spell the difference between finding meals palatable and losing interest in eating, at a time when patients need all the strength and nourishment they can get.

But Jacobs, who recently published a self-help book "The Silver Lining: A Supportive and Insightful Guide to Breast Cancer," adds a note of caution. Like many other patients she discovered that the food she ate during chemo was nearly impossible to consume once treatment was over. The memories and associations were just too strong. As a result, many patients choose not to eat their favorite foods during chemo therapy, so that when it is over, they can still enjoy the food they always loved.

In a 6-quart pot, bring the broth, coconut milk, ginger, shallots, lime leaves, lemongrass, and 1/4 teaspoon salt to a slow boil over medium heat. Let the ingredients infuse their flavor into the liquid for about 20 minutes. Decrease the heat to low and continue to let the broth develop for another 30 to 40 minutes. Remove the shallots, lime leaves, and lemongrass with a slotted spoon. Add the sweet potatoes and turn the heat back up to medium. Cook the sweet potatoes until tender, about 15 minutes.

In a blender, purée small batches of the broth and potatoes until smooth. Repeat until all the soup is blended. Reheat, ladle into soup bowls, drizzle with the lime juice, and garnish with the mint, cilantro, and some toasted shaved coconut. Yum!